looks like the end of Q3-2016 or start of Q4-2016 http://wccftech.com/intel-kaby-lake-q3-2016-cannonlake-2017/
but keep in mind that is the mobile platform road map not the desktop one, though they shouldnt be far off. maybe intel has changed it for both about the same time, but i always remember them having Mobile cpus to oem first before desktop parts.
We've seen early skylakes to make 5ghz on air in first leaks but 99% of retails can't make it. I wish to see cheaper 8-10 cores but more for benching as for gaming even 3-4 year old cpus are good enough. There is a chance that zen will fill the gap between 4 cores and overpriced Intel 8+ cores.